Sensors for automobiles, such as anti-lock brake, gearbox, camshaft, and crankshaft sensors, transmit an output data signal on a single pin. The output data signal, for example, in the case of a crankshaft sensor, uses a single bit to indicate the position and/or rotational speed of the crankshaft. Using a single pin to transmit the output data signal reduces cost, weight, and/or risk of error.
In addition to the output data signal, there is a desire to transmit the raw, multiple bit internal data signal for diagnosis purposes. There is no additional pin available for transmitting this internal data signal. Either the output data signal or the internal diagnostic data signal is transmitted, but not both signals at the same time.